Iray and hair - how to make it look good?

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Hair has been a challenge for me as well. Some hair looks good, some hair looks awful and it seems to come down to how it's made and what trans maps I have to work with.

...yeah, Osean Hair is one that doesn't seem to do well in Iray. Looks way too thin almost to the point of making it look like the character is suffering from early stages of radioactive exposure.

Fig. 1. Iray

Fig. 2. 3DL

(for some reason the order of the images were flipped by the forum software)

could have something to do with the 'blacks' of the trans map not truly or fully black and the whites not being fully white for that matter. There was mention of the incorrect gamma being applied to the trans map could by default set blacks to a gray shade which would make more of the geom transparent.

I use Micah Hair from AprilYSH for a character, Jason Dalton, in the book series I mentioned in an earlier post. I had already modified the transparency map to make it look less solid and more like hair. And with a bit of tinkering, it looks very good in Iray.

As this thread is about how to make hair look good, I spent some time documenting what settings I was working with and how they affected the hair. For this, I used the standard blonde mat for Micah Hair.

The first image below is a side-by-side comparison of Micah Hair with the default Iray Uber Base shaders applied on the left and then with the Cutout Opacity set to 1.75 on the right. As you can see, the base shader does a pretty good job of converting Micah Hair. It's pretty usable as is. Exaggerating the Cutout Opacity, on the other hand, leaves Jason looking like he's addicted to hairspray.

I played around a lot with the Base Color and ended up leaving it as is. But it was pretty fun to make it a bright blue. And it really showed where the Base Color is applied, and how strongly.

Another thing I've seen in various threads of the forum is how using translucency leaves areas of the hair white. That is a function of the Translucency Color, which is set to white by default when you set Translucency Weight to anything but 0.00. Early in this thread, Hellboy mentioned setting the weight to 0.5 and using th same color as the hair. I think the right weight to use may be dependent on the hair object. I liked the effect of 0.25 on Micah Hair. Any higher and it didn't look good to me.

The second image below has three versions of Micah Hair side-by-side with Translucency Weight set to 0.25. The hair on the far left uses the default white Translucency Color. In the middle, the Translucency Color was changed to black. And on the far right, the Translucency Color was set to a color from the blonde texture. (I used a color picker to select a mid-range color.)

I think the white is too extreme, but both the black and tan colors seem to work well as the Translucency Color for the blonde hair.

Until you set Translucency Weight, the other settings for translucency are hidden. (This is true of a good number of Iray options.) The third image is another side-by-side comparison, showing the editor settings both before and after weight has been dialed in.

The uninspiring lighting setup was intentional, and included the sun node assigned to a DistantLight directly in front of the figure and a photometric spotlight on either side pointing behind the figure. For the translucency tests, another photometric light was directly behind the figure pointing to the back of his head. (Doesn't seem to have made any difference in the hair, though.) All test renders were cancelled 10-15 minutes into the render, before the images reached 1% convergence.

...thank you. this works great.

BTW to reveal all the controls you can click on "Show Hidden Properties".Note that unlike hidden morph dials, dials that are hidden in places like the Surfaces Pane and Render settings don't do anything this way. They are hidden because they don't make sense for the settings you have chosen.

For example, under the emission channel you get no settings unless you change the color to something other than black. Changing the settings by using "Show Hidden" don't change anything, it still won't emit or glow.

Hair has been a challenge for me as well. Some hair looks good, some hair looks awful and it seems to come down to how it's made and what trans maps I have to work with.

...yeah, Osean Hair is one that doesn't seem to do well in Iray. Looks way too thin almost to the point of making it look like the character is suffering from early stages of radioactive exposure.

Fig. 1. Iray

Fig. 2. 3DL

(for some reason the order of the images were flipped by the forum software)

Convert to the Iray shader and then turn the opacity up to more than 1

Below are 2 renders one with the opacity set to 1 and the other at 1.75.

*edit added bg to images and combined for clarity

if you're finding yourself messing around with opacity level it can only be because blacks are not truly or fully back same for white for the trans map. Much discussed topic in Reality forum in RDNA and very much considered solved.

Just removed off the opacity map and it looks like she's waring one of those string mop heads

Exactly. I know my issue with the Lanny hair comes down to the Opacity map but my skills aren't up to making whatever change I need to make in photoshop. I think it comes down to 3Delight vs Iray just uses opacity maps differently.

blacks are not black, same for white for trans maps. consider that gamma correction needed before trans maps are used as intended in iray, very linear color space renderer makes no exceptions. trans maps that go in as jpeg are assumed to have gamma 2.2 applied and not corrected by iray, something along those lines. HDRs stay at gamma of 1.0.

Will LAMH work in Iray if brought in as OBJ? Worked with Lactis Imagery free pubic hair made with zbrush fibermesh as obj renders very quickly in Iray making me think Iray is not limited by number of geometry polys or tris.

Will LAMH work in Iray if brought in as OBJ? Worked with Lactis Imagery free pubic hair made with zbrush fibermesh as obj renders very quickly in Iray making me think Iray is not limited by number of geometry polys or tris.

Yes, but the poly count still 'counts' toward the total of your scene memory usage. So a nice thick, fine hair or fur is going to eat up a bunch of space. The nice thing is, it doesn't have to have image textures to it...

Turn up the bump (1 is a lower value in Iray than 3Delight). If the hair doesn't already have SubD, add it in the scene tab button and turn it up to 2 or so to make it look smoother and less jagged, too. You can also profitably fiddle with the gloss settings.

Thanks SickleYield, I did try what you suggested but could not find a Sub D level option for this hair. Not sure how to add it if it's not there.

The scene was lit using an HDRI called Sierra Madre B provided free from http://www.hdrlabs.com/sibl/archive.html and after a photographer on deviantart.com recommended leaving the camera headlamp on for Iray, I did so for this render.

The base bump was originally an extremely low value of something like 0.095 and I increased it to 20.0 :ohh:
I also made a copy of the original bump map, and in a photo edit program increased the contrast so the faint bump lines appeared a lot darker. I then used this edited version of the bump map.
I also increased the glossy roughness to 0.40 and changed the Glossy Color Effect to 'Scatter and Transmit'.

Now, I don't know how much this tweaking actually improved the hair, but it certainly looks good on my monitor from a distance of two feet :lol:
How it would appear in a printed version is anyones guess at the moment !
Also, I am not so sure that if we go past a certain level of tweaking individual settings, then it fails to make any further improvements. Looking at SWAMS promotional pictures for this hair product they look extremely good. I wonder what program they were rendered in.

As a final observation, I am amazed how clothing renders so realistically with no added Iray shaders or tweaking settings. I'm sure I read somewhere in these forums that Iray converts them automatically. What a pity the same doesn't happen with hair, and skin textures. :)

I replaced my modified Bump map with the Sai Fon Hair original map. The blonde hair now appears lighter as it was meant to be.

I also found one of the Sai Fon Hair texture maps that was being used in 3Delight was nowhere to be seen in the surfaces tab when the Iray Uber Base shader was applied. Maybe this was because it wasn't required ? I have no idea on that.
However, I placed it in the Normal Map section and weird shadows appeared in the hair. So I then placed it in the Base Thin Film section and adjusted the level to 9500.00

The hair has appeared to render with a lot finer detail. View at original size.

There are so many variables, that it would take weeks of rendering trying different options and values, to see if what I did here was of any real significance. To my eyes the hair does look more defined in this second image.

looks good Musicplayer. I've also thrown the 'Displacement' (not Bump) way out like that for some hair in the past in 3delight.

Here I just wanted something close. I ctrl-clicked the silk shader, and then adjusted the backing color for the maps. This trick probably will not work so well on less flat hair styles with lots of fringe or stuff (like crazy-locks for example). I could have done much more, tho I was mostly working on lights at the time.

This is the setup I am currently testing for hair. So far it looks wonderful on each hair model I have tried it on and with each color the hair model comes with. Some example renders have been composited below for your reference. Also of note, in the following settings list I have put items that I left at default values in italicized font to help you more quickly find the important settings. If there is a way I can make this as a preset and share it so you can try it out yourself, please let me know and I will do that if desired.
My favorite things about this arrangement: Only needs a diffuse and bump map, and has that glistening translucency effect that human hair strands have when held up to the sun.
Lighting: 1 photometric point light and Riverside Park from http://hdrlabs.com/sibl/archive.html.

EDIT: Oh, I should also note in case one is wondering, for the red haired Gia Hair I duplicated the hair node, and added 0.50% scale to it, posed it a little different, and set the scalp on the duplicate to 0 opacity - this gave the hair much better volume. =)

I assume that HDRI is labled "hdrvfx_0008_nyany.zip" from that page, quite a bit down from the top? HDR-VFX Promo Library?

One of my biggest issues with so many light setups being used, is they cost money, and that makes the availability for others to try duplicating the test conditions difficult. Especially when it's a light set that is no longer available for purchase, or they simply don't know where it came from, lol. It's why my test chamber only uses lights that came with Daz Studio.

The other, is I've never had a chance to do anything with any HDRI maps. There are plenty of threads on that, and now I have a free map to try it with. Thanks Taigafaeri and Hdrlabs.

This is the setup I am currently testing for hair. So far it looks wonderful on each hair model I have tried it on and with each color the hair model comes with. Some example renders have been composited below for your reference. Also of note, in the following settings list I have put items that I left at default values in italicized font to help you more quickly find the important settings. If there is a way I can make this as a preset and share it so you can try it out yourself, please let me know and I will do that if desired.
My favorite things about this arrangement: Only needs a diffuse and bump map, and has that glistening translucency effect that human hair strands have when held up to the sun.
Lighting: 1 photometric point light and Riverside Park from http://hdrlabs.com/sibl/archive.html.

EDIT: Oh, I should also note in case one is wondering, for the red haired Gia Hair I duplicated the hair node, and added 0.50% scale to it, posed it a little different, and set the scalp on the duplicate to 0 opacity - this gave the hair much better volume. =)

I posted this in the skin thread, but I think I should probably cross post it here, as it is my hair settings.

Some notes:

Translucence can be spotty. If you’re using a hair where the hair from the back of the neck is very noticeable from the front, it might be best to turn it off (This is more a problem with the nature of trans-mapped hair)

I replace all hair textures with OOT’s since, it makes it easier for me to make presets and get predictable results I also go into the image editor and set the horizontal tiling to 2 or higher to make it crisper (when did daz add that? its made my life so much easier. I used to do do many weird tricks to try to tile textures without effecting opacity) You don’t have to do that, but if you have any favorite hair textures that are tillable, I recommend it

These settings are for brown hair, for blond hair I have to turn the spec way up.

The other reason I recommend tiling textures is editing purposes, I did 99% of the setup on a sphere, It renders quickly, so its easy to have your aux view in rendered mode, and its way easier to see which way the anisotropy is actually going.

The other image is the displacement map I’m using it makes the hair strandier, and is especially useful on flatter hairs. Watch out for the displacement on hairs that have modeled strands, I forgot to turn down the subD on the strands on one of goldtassel’s hairs and slowed my computer to a crawl. When I turned it off for the strands it did look fantastic though.

If you buy any of their recent-ish hairs they're all designed to take the same textures (other than transparency obviously). Its pretty genius actually. Less work for them and less files for the end user.

After looking its more their hairs at r'ocity (in particular anything labeled hairblending), but Milena hair here looks like it would also work.

I assume that HDRI is labled "hdrvfx_0008_nyany.zip" from that page, quite a bit down from the top? HDR-VFX Promo Library?

One of my biggest issues with so many light setups being used, is they cost money, and that makes the availability for others to try duplicating the test conditions difficult. Especially when it's a light set that is no longer available for purchase, or they simply don't know where it came from, lol. It's why my test chamber only uses lights that came with Daz Studio.

The other, is I've never had a chance to do anything with any HDRI maps. There are plenty of threads on that, and now I have a free map to try it with. Thanks Taigafaeri and Hdrlabs.

Thank you, and Thank you to Scott as well. Yes, when you unzip that one its files are called nyany - that confused me too. You'll want to plug the hdrvfx_nyany_1_n2_v101_Ref file into the environment map slot in render settings for best results. I found that using the crisp image, instead of the blurry lights only image, gives really nice reflections on the eye surfaces. My scene has one photometric point light above and to the left of the girl, and set behind her at shoulder level - both 80,000 lumens and 0k tempurature. I added those for better testing of the translucency and highlighting of the hair. Hopefully, that will give you a good duplicate scenario to test with and provide you with similar results.

Since that post I made some adjustments to my settings that I think are better. I'll run another series of comparison renders and post the settings soon. I'll keep using those free hdri maps from hdrlabs for testing so the scene can be duplicated easily.
Oh, do note that they are not usable for commercial renders. They sure are perfect for learning though ^_^

Okay, fine tuning and test rendering complete. Here is everything I used, so hopefully you can duplicate the experiment and get the same results -minus my personal character shape (I couldn't stand using the default shape, sorry!) and skin settings (I can share those too if desired). I did my best to stick with things that are available as default with D|Studio so no one would have to buy anything extra to practice with. However, I ended up using the mats SWAM made for their Jewel Hair for the final testing, but it looked just as good with the mats they made specifically for Toulouse Hair. Before I finished this round I did some more studying on human hair. This article was very helpful: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3250015/
From what I read there, I decided to treat the backscattering and refraction colors as the "melanin" layers and the top coat as the specular reflection from the "scales". I suspect that if you treat the backscattering color as pheomelanin and tint it with reds or yellows, and the refraction color as the eumelanin and tint it with browns and blacks... you could get some really visually interesting results. For these settings they are pure white though and use the color maps that normally go in the diffuse color slot in 3Delight shaders as the pigmentation instead. This because I was striving for a good balance between simplicity and reality. Also, you can tint the top coat color for richer tones, but since the article mentioned that it reflected the color of the light shining on it rather than scattering more of the pigmentation of the hair, I chose to make it pure white as well to enable it to do just that. I did test multiple HDRs for different light colors and levels and the settings responded very well. =)

if you're finding yourself messing around with opacity level it can only be because blacks are not truly or fully back same for white for the trans map. Much discussed topic in Reality forum in RDNA and very much considered solved.

Try taking the opacity map to an image editor like Photoshop and change gamma to 2.2 using Exposure adjustment. Be sure to backup the original opacity map first. Your opacity map should then work as expected.

(I just checked an AprilYSH hair transmap in Photoshop and the blacks and whites really are 0,0,0 and 1,1,1)

(Though I'm finding Refraction doesn't work well for the Xylia hair I'm playing with)

I haven't gotten there yet, [sobbing] I'm still working on light basics. Considerable progress with that after the new Iray capable graphics card.

I have that hair I was going to try on a 'R' figure by Silver. I may very well change the figure tho the Xylia Hair, is a very nice touch for showing the face and ears (Especially for Elves and Fairies). That and the Sora Hair (no favorite, I like them both).

These settings appear to have completely fixed all the hair problems I was having. I actually made myself a little preset shader with these values - I still have to go in and add the diffuse, bump and opacity maps, but these settings have saved me so much tweaking time that it's no problem at all to update a couple of things manually.

I've been playing a lot with Xylia hair and I'm learning that it's WAY more robust for Iray than I had thought.

Mainly I've been learning how much is me doing it wrong. ;)

Agreed, I did nothing here in Iray. I loaded the hair as is, and applied that blue color preset. That was All I had managed to do, before running off to work on a set of calibrated test lights for my test chamber (I'm still doing that).

adentonclark That is incredibly good news. Presets do tend to make life easier, especially if all that's needed is moving a few maps from one slot to another, then saving that as a scene subset (or material Preset).

uh.
"Shader preset" is only for a single surface, and can be applied to any surface.
"Material(s) Preset" is for a collection of surfaces (there is a selection box to chose what), and only works on items that have the same zone names.
"Scene Subset", is kind of like a save Scene, except you can select what you want to save.

There is the menu, and the '+' thing in the content library....

The menu way, opens the usual save dialog (Windows, and I think MAC).
The '+' thing in the content library, only saves the 'Whatever' in the path that is open. Unless you change the path in the window that opens up for the save file name thing, before the dialog asking what parts to save appears.